MOLLUSCA. TROCHUSID^. 
Tkochus. 
S25 
sulcus around the middle ; base flattish- — Sower. Min. Conch, t, ccxx. f. 3. — 
Inferior Oolite. 
15. T. pallium. — Conical, depressed, with concentric furrows, and diverging 
striiE ; whorls above depressed, with many tubercular undulations ; in the 
middle flattened, with a longitudinal band ; base convex, umbilicated ; mar- 
gin largely crenulated.—iS'owcr. Min. Conch, t. ccxxi. f. 1. — Inferior Oolite. 
16. T. tiara, — Depressed, conical, with diverging striae ; volutions obscure- 
ly bicarinated, deeply undulated above, concentrically striated beneath ; base 
convex, with a large pillar-cavity.— 5'o^tw. Min. Conch, t. ccxxi. f. 2 — Green 
Sand. 
17- T. Sedgwicki. — Conical, smooth ; base carinated ; whorls concave above, 
convex below; margin and base striated.— Min. Conch, t. cclxxii. f. 1. 
— Suffolk Crag. 
18. T. imhricatus. — Pyramidal, with several transverse threads upon each 
whorl, crossed by fine longitudinal striae ; whorls angidar, imbricating, flat 
above, very convex beneath ; pillar-cavity closed.— >S'ower. Min. Conch, t. 
cclxxii. f. 3, 4 — In Lias Clay. 
19. T. Conical, transversely reticulato-striated ; whorls bicari- 
nated ; base convex. — Sower, Min. Conch, t. cclxxii. f. 2. — Upper Oolite. 
20. T. Conical, short, umbilicated ; sides straight ; edge obtusely 
carinated ; base convex, reticulato-striated ; in the centre of the upper part 
of the whorls, is an elevated band, crossed by curved striae ; aperture rhom- 
boidal — Sower. Min. Conch, t. cclxxviii. f. 1 — Chalk Marl. 
21. T. extensus — Depressed, conical ; above rugged, obliquely striated ; 
beneath convex, smooth ; base expanded, with a broad undulated thin mar- 
gin ; aperture oblong ; pillar-cavity not plicated, closed when old. — Sower. 
Min. Conch, t, cclxxviii. f. 2, 3. — London Clay. 
22. T. monilifer. — Conical, transversely striated ; volutions rather convex, 
with three rows of tubercles, and crenated edges ; base slightly convex, bear- 
ing six rows of granules ; aperture quadrangular ; pillar-cavity, along one 
edge of the aperture, truncated. (T. nodulosus, Brander, Foss. Hant. f. 6.) 
— Sower. Min. Conch, t. ccclxvii.— Clay. 
23. T. linearis.—’-'’ Conical, wreaths slightly convex, transversely striated, 
with a prominent line along the centre and base of each volution ; base flat ; 
umbilicus obscured by the last volution ; aperture transversely depressed.” — 
M'antell.) Geol. Suss. 1 10. t. xviii. f. 17* In grey chalk-marl. Indications of three 
other species, from the sam.e formation, are given by Mr Mantell, ib. 1. xviii. 
f. 7. fi 9. and 16. 
Gen. solarium. — P illar cavity spreading, and crennlated 
at the margin of the whorls. 
1. ^.patulum Depressed, whorls smoothish; margin keeled and crenulated; 
margin of the cavity strongly denticulated. Sower. Min. Conch, t. xi. ; lower 
right hand figures — In London Clay. 
2. S. discoideum. — Discoid, outer edge sharply carinated ; edge of the pillar- 
cavity rounded, transversely wrinkled ; aperture obliquely elliptical, pointed 
at each end. Sower. Min. Conch, t. xi. ; upper right hand figures. — London 
Clay. 
3. S. conoideum. — Conical, smooth ; aperture quadrangular ; pillar-cavity 
deep, narrow. — Sower. Min. Conch, t. xi. ; three middle figures. — Upper Oolite. 
